Reconstruction of the anterior cruciate ligament (ACL) of the knee has become a common surgery. It is estimated that orthopedic surgeons do more than 100,000 ACL reconstruction surgeries each year in the U.S. alone. The long-term success rates are somewhere between 75% and 90%. As good as that is, it still leaves an awful lot of people who face ongoing problems or a second surgery to fix an ACL reconstruction with poor results.
Revision surgery is done to fix problems that occur after an earlier surgery. Revision surgeries on a reconstructed ACL can be very tricky. In this article, the authors give an overview of treatment for failed ACL reconstruction. They discuss reasons for failure and a systematic approach for doctors to take in these cases.
The authors stress that it is especially important to figure out why the reconstruction failed in the first place. There are many possible causes of ACL reconstruction failure. Was it related to ligament laxity or other problems in the knee? Was it related to doing too much before healing, surgical technique, or graft failure? Early failure–within six months–tends to be related to problems stemming from the surgery or overly aggressive rehabilitation. Failure that occurs over a year after revision is more often due to a new injury.
The authors list surgical problems that can cause failure. Many factors, including surgical technique and abnormalities of individual knees, can contribute to surgical problems:
- missing the mark in the knee bones where the ligament should go
- not lining the ligament up right, causing it to get pinched as the knee moves
- not placing the right amount of tension on the graft
- not securing the graft tightly enough
- damaging the graft ligament when it is being implanted
- not treating other problems in the knee, including other ligaments that are too loose to hold the knee in proper position
- failure of the graft to heal well and to become part of the knee
- re-injury of the knee after surgery, which happens in up to 10% of athletes.
The authors recommend that surgeons do an especially thorough evaluation of patients before doing a revision surgery. The evaluation should include:
- a detailed medical history
- a detailed physical examination, which focuses on the anatomy of the injured knee and the way it moves
- various imaging tests–X-rays, bone scans, CT scans, and possibly an MRI–to learn as much as possible about the knee’s condition and the problems with the original surgery.
The surgeon will use this information to make many difficult decisions about the best way to do the revision surgery–how to change the placement of the graft, and what kinds of graft and hardware to use.
The authors conclude that it is especially important that surgeons be clear with their patients about the problems with revision surgery on the ACL. It is a complex surgery, and it is impossible to predict its outcome. The results are usually not as good as those of first ACL reconstruction surgeries. ACL revision requires the best efforts of both the surgeon and the patient.